The research project is oriented towards constructing model biological environments, for heme and hemin, that impose kinetic, thermodynamic and structural characteristics on the metalloporphyrin similar to those of hemoproteins. Studies have revealed that ironporphyrins, regardless of oxidation state are intercalated into cationic, neutral and anionic micelles of cetyltrimethylammonium bromide, Triton X-100 and sodium dodecylsulfate respectively. Spectral and kinetic properties of intercalated hemin in micelles with cyanide, cyanate, histidine and imidazole have been investigated, utilizing PMR, fluorescence, UV-vis spectra and stopped-flow techniques. These studies reveal complex mechanisms that ultimately lead two ligands reversibly binding to the axial positions on the metalloporphyrins. Hemes intercalated in the hydrophobic core of micelles rapidly (approximately 10 msec) react with dissolved 02 and immediately oxidize irreversibly to hemin. This suggests that the hydrophobicity associated with globular proteins is not solely responsible for maintaining an Fe(II) oxidation state in hemoglobin or myoglobin. Heme with two histidines or imidazoles bound axially and intercalated in selected micelles also is irreversibly oxidized by removal of one axial ligand with subsequent attack of 02 and concurrent oxidation.